Objective: To study the effects of Rhizoma Polygoni Cuspidati on expression of transforming growth factor beta 1(TGF-β1) in rats with pulmonary fibrosis induced by bleomycin.Method: 120 male SD rats were randomly divided into five groups: the control group(n=30),the bleomycin(BLM) model group(n=30),the Rhizoma Polygoni Cuspidati prophylactic group(n=30),the 7 th day treatment group(n=20) and the 28 th day treatment group(n=10).The rat models of pulmonary fibrosis were established by intratracheal injection ...